DESCRIPTION: Fall-related injuries are a major problem within industry and the general society when measured in terms of economic losses and human suffering. Older adults in particular are more susceptible to fall-related injuries due to higher fall rates and a greater likelihood of injury from a fall. The well documented reduction in muscle strength that occurs with aging is thought to be one factor contributing to the higher fall rates in older adults. Despite substantial evidence implicating age-related strength reductions in the higher falls rates among older adults, the specific biomechanical mechanism by which strength reductions contribute to falls remains unclear. Based on results from a previous study, a substantial number of falls occur after tripping even though individuals are able to complete a step in an attempt to recover their balance. It is thus hypothesized that events subsequent to step completion are critical to balance recovery. The current study will use an existing experimental model of balance recovery to investigate insufficient joint torques in the stepping leg, after taking a step to recover balance, as a mechanism contributing to tripping and falling accidents. If these torques are insufficient, they would not adequately decelerate trunk angular momentum and/or would not prevent the stepping leg from collapsing. As a result, the individual would fall. The two projects outlined in the proposed research will 1) establish baseline measurements of stepping leg joint torques during balance recovery in a young adult population, and 2) compare measurements of stepping leg joint torques in healthy older adults during balance recovery to those of young adults. Completion of these projects will provide specific information towards identifying biomechanical mechanisms that contribute to falls in older adults. This information can be used to develop specific intervention strategies, such as weight training regiments, aimed at fall prevention.